Brake



R. S. SANFORD m v. x

. INVENTOR. F0, i SHA/FUFO w 1. KN

atente Roy S. Sanford, New York, N. if., assignor to Bendix Aviation Corporation, South Bend, Intl., a corporation of Delaware ,Original application December 21, 1932, Serial Divided and this application October 12, 1935, Serial No. 44,663

2 Claims.. (Ci. 188-264l This invention relates to brakes, and isuillustrated as'embodied in novel brake drums having means for absorbing part of the heat developed during brake application. An object of the in- 5 vention is to minimize the temperature attained by the drum during braking, by absorbingv part of the heat. v

V'One desirableconstruction includes a drum formed with an annular peripheral chamber con- 0 taining heat absorbing material. In one embodiment this material is preferably one having a low boiling point and a high latent heat -of evaporation, so that the latent heat of vaporization is utilized to absorb braking heat. Such materials are sulphur dioxide and ethyl chloride.

This embodiment also illustrates the use of ribs arranged internally ofthe annular chamber to transmit heat efficiently to the heat absorbing material.

In another embodiment airis utilized as the heat absorbing material, and a relief valve is arranged to discharge'into the drum against the friction means some of the air as therlslng temperature increases the pressure inside the annu- 25? lar chamber. Preferably this drum is provided with a `check valve opening into the chamber from the exterior of the drum, to provide for replacement of the air as the drum cools.

The above and other objects and features of 30 the invention, including various. novel combina' In this embodimen the drum is formed with an annular periphera chamber H4, partlyl filled (by removing a plug H6.) with a material hav/- ing a low boiling point and a high latent heat of evaporation, such as sulphur dioxide or ethyl,

chloride. The drum is preferably formed with heat transmitting ribs lili projecting into the annular chamber. Thus a considerable part oi the heat of braking may be absorbed in Vaporizingthe iiuid in chamber lill, thereby minimizing its effect on the drum and the tires.

In Figure 2, the drum 23 is'formed'with an annular peripheral chamber |42 containing air as the heat absorbing material. The air-- is. sucked from the exterior of the brake into the chamber |42, as the brake cools on after'having been applied, through an inwardly-opening check valve llt. Whenthe brake is applied, the air absorbs part of the heat, expands, and part of it is forced into lthe interior of the brake dru'm through a relief valve |46, carrying with it the heat which it has absorbed. 1

While two illustrative embodiments have be'en described in detail, itis not my intention to limit the scope of my invention to those particular embodiments, or otherwise than by the terms of the appended claims. The present application is a division of Y my application No. 648,300, led December 21, 1932.

l. A'brake drum having an annular peripheral chamber containing air, and provided with a relief valve and with a check valve opening into v said chamber.

2. A brake drum having an annular peripheral chamber containing air, and provided with a relief valve opening into the interior of the drum 'Y nov s; SANFORD. 

